Yes, I use Ubuntu. In my case I don't need backup IPs but it's interesting. Nice! It works! But, I still have one problem, my application restart when nginx reload, but I think it's not pertinent of this thread. Explaining my case, my application is a Rails App using Passenger, I think will be more interesting now change to Unicorn. thanks!
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joaorvmaiaNov 8 '12 at 11:57

I guess you could take a look at this gist which shows how to issue certain signals to Unicorn from Capistrano. Good luck.
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deRailedNov 8 '12 at 15:50